Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 03 May 2015, 22:33

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# Is -x < 2y ?

Author Message
TAGS:
Senior Manager
Joined: 04 Jan 2006
Posts: 280
Followers: 1

Kudos [?]: 20 [0], given: 0

Is -x < 2y ? [#permalink]  30 Jan 2007, 20:25
1
This post was
BOOKMARKED
00:00

Difficulty:

25% (medium)

Question Stats:

74% (02:21) correct 26% (01:18) wrong based on 100 sessions
Is -x < 2y ?

(1) y > -1
(2) (2^x) - 4 > 0
[Reveal] Spoiler: OA
Director
Joined: 05 Feb 2006
Posts: 902
Followers: 1

Kudos [?]: 51 [0], given: 0

I choose C...

Is x>-2y

1) insufficient, we do not know anything about x

y could be negative: -0,5 or positive 1, 3, 2.5

2) insufficient, we do not know anything about y

x>2

1+2) Sufficient. Take worst case scenario: y=-0.99, x=2.1
Plug into
x>-2y

2.1>1.98...
SVP
Joined: 01 May 2006
Posts: 1805
Followers: 8

Kudos [?]: 98 [0], given: 0

(C) for me

-x < 2y <=> y > -x/2

In a XY Plan, Y is above the line -x/2. I prefer to solve this DS with the XY plan.

Stat1
y > -1. This brings us to y above the line y=-1. The area covered could be either above -x/2 (when x>0) or below -x/2 (wehn x<10). (Fig1)

INSUFF.

Stat2
(2^x) - 4 >0
<=> 2^x > 4 = 2^2
<=> x > 2

In the XY plan, it does mean that the concerned area is at right of the line x=2. One more time, their is 2 case, y could be either above the line -x/2 (when y > 0) or below the line -x/2 (the point (3,-100)). (Fig2)

INSUFF.

Both (1) and (2):
x > 2 and y > -1 represents an area with a not attainable vertice at (-1;2). By drawing the line -x/2 and this point, we observe that this point is on the line. Thus, the whole area of points such that x>2 and y>-1 is above the line -x/2. (Fig3)

SUFF.
Attachments

Fig1_y sup -1.GIF [ 3.17 KiB | Viewed 1828 times ]

Fig2_x sup 2.GIF [ 3.07 KiB | Viewed 1828 times ]

Fig3_x sup 2 and y sup -1.GIF [ 2.91 KiB | Viewed 1870 times ]

SVP
Joined: 05 Jul 2006
Posts: 1519
Followers: 5

Kudos [?]: 115 [1] , given: 39

1
KUDOS
Is -x < 2y
(1) y > -1
(2) (2^x) - 4 > 0

is

2y+x>0

from one we ve no info about x ......insuff

from two

2^x > 2^2

ie: x>2........no info about y insuff

both together

x>2 , y>-1

thus x+y>1

we need to prove that 2y+x>0 ie +ve

x is always +ve

and the maximum -ve value y can be multiplied by two is less than 0

thus C is my answer too
Senior Manager
Joined: 04 Jan 2006
Posts: 280
Followers: 1

Kudos [?]: 20 [0], given: 0

yezz wrote:
Is -x < 2y
(1) y > -1
(2) (2^x) - 4 > 0

is

2y+x>0

from one we ve no info about x ......insuff

from two

2^x > 2^2

ie: x>2........no info about y insuff

both together

x>2 , y>-1

a little bit more work from the quote above.

x > 2 (equation 1)
y > -1 or 2y > -2 (equation 2)

(equation 1) + (equation 2)... x + 2y > 2 + (-2)
x + 2y > 0
x > -2y
-x < 2y (this is the same as the question.)

Director
Joined: 24 Aug 2006
Posts: 754
Location: Dallas, Texas
Followers: 5

Kudos [?]: 45 [0], given: 0

Re: DS: Property of Number [#permalink]  01 Feb 2007, 23:34
We have to determine whether:-x<2y>-2y

From (1) y>-1 ---- insufficient

From (2)
2^x >2^2
x>2 -----------------insufficient

Combining (1) and (2)
We can say x > -2y

(C)
_________________

"Education is what remains when one has forgotten everything he learned in school."

Intern
Joined: 23 Nov 2010
Posts: 2
Followers: 0

Kudos [?]: 0 [0], given: 0

Re: DS: Property of Number [#permalink]  03 Dec 2010, 10:06
I go for (C)
1) y>-1
NOT SUFF
2) 2^x - 4 >0
NOT SUFF

Combine:
From 1: y>-1 <=> 2y>-2
From 2: 2^x -4>0 <=> 2^x>2^2 <=> x>2 <=> -x<-2
Therefore: -x<-2<2y <=> -x<2y. Here we go.
Math Expert
Joined: 02 Sep 2009
Posts: 27170
Followers: 4226

Kudos [?]: 40957 [0], given: 5576

Re: DS: Property of Number [#permalink]  03 Dec 2010, 10:22
Expert's post
devilmirror wrote:
Is -x < 2y
(1) y > -1
(2) (2^x) - 4 > 0

Quite an old thread is resurrected.

Is -x<2y?

Is $$-x<2y$$? --> rearrange: is $$x+2y>0$$?

(1) y>-1, clearly insufficient as no info about $$x$$.

(2) (2^x)-4>0 --> $$2^x>2^2$$ --> $$x>2$$ --> also insufficient as no info about $$y$$.

(1)+(2) $$y>-1$$, or $$2y>-2$$ and $$x>2$$ --> add this inequalities (remember, you can only add inequalities when their signs are in the same direction and you can only apply subtraction when their signs are in the opposite directions) --> $$2y+x>-2+2$$ --> $$x+2y>0$$. Sufficient.

_________________
SVP
Joined: 06 Sep 2013
Posts: 2035
Concentration: Finance
GMAT 1: 710 Q48 V39
Followers: 24

Kudos [?]: 294 [0], given: 354

Re: Is -x < 2y ? [#permalink]  01 Jan 2014, 05:42
devilmirror wrote:
Is -x < 2y ?

(1) y > -1
(2) (2^x) - 4 > 0

Statement 1

y>-1 but no info about 'x'. Not sufficient

Statement 2

x>2, but no info on 'y'. Not sufficient

Statements (1) + (2) together

y + x/2 > 0?

Well, x>2 so x/2>1

And y>-1, so yes it will always be more than zero

Hence C is sufficient

Hope it helps

Cheers!
J
Senior Manager
Joined: 06 Aug 2011
Posts: 409
Followers: 2

Kudos [?]: 79 [0], given: 82

Re: DS: Property of Number [#permalink]  06 Feb 2014, 07:41
Bunuel wrote:
devilmirror wrote:
Is -x < 2y
(1) y > -1
(2) (2^x) - 4 > 0

Quite an old thread is resurrected.

Is -x<2y?

Is $$-x<2y$$? --> rearrange: is $$x+2y>0$$?

(1) y>-1, clearly insufficient as no info about $$x$$.

(2) (2^x)-4>0 --> $$2^x>2^2$$ --> $$x>2$$ --> also insufficient as no info about $$y$$.

(1)+(2) $$y>-1$$, or $$2y>-2$$ and $$x>2$$ --> add this inequalities (remember, you can only add inequalities when their signs are in the same direction and you can only apply subtraction when their signs are in the opposite directions) --> $$2y+x>-2+2$$ --> $$x+2y>0$$. Sufficient.

I chose C.. thats correct.. bt with different approach

bt Bunuel I didnt get this highlighted thing?? How did u do that?
_________________

Bole So Nehal.. Sat Siri Akal.. Waheguru ji help me to get 700+ score !

Math Expert
Joined: 02 Sep 2009
Posts: 27170
Followers: 4226

Kudos [?]: 40957 [0], given: 5576

Re: DS: Property of Number [#permalink]  07 Feb 2014, 04:12
Expert's post
sanjoo wrote:
Bunuel wrote:
devilmirror wrote:
Is -x < 2y
(1) y > -1
(2) (2^x) - 4 > 0

Quite an old thread is resurrected.

Is -x<2y?

Is $$-x<2y$$? --> rearrange: is $$x+2y>0$$?

(1) y>-1, clearly insufficient as no info about $$x$$.

(2) (2^x)-4>0 --> $$2^x>2^2$$ --> $$x>2$$ --> also insufficient as no info about $$y$$.

(1)+(2) $$y>-1$$, or $$2y>-2$$ and $$x>2$$ --> add this inequalities (remember, you can only add inequalities when their signs are in the same direction and you can only apply subtraction when their signs are in the opposite directions) --> $$2y+x>-2+2$$ --> $$x+2y>0$$. Sufficient.

I chose C.. thats correct.. bt with different approach

bt Bunuel I didnt get this highlighted thing?? How did u do that?

$$2y+x>-2+2$$ --> re-arrange the left hand side as x+2y. As for the right hand side: -2 + 2 = 0. So, we get $$x+2y>0$$.

Hope it's clear.
_________________
Re: DS: Property of Number   [#permalink] 07 Feb 2014, 04:12
Similar topics Replies Last post
Similar
Topics:
3 Is 0 < (x−y)/(x−2y) < 1? 5 13 Feb 2015, 07:45
If X/Y > 2 . Is 3X + 2Y < 18 ? 1. X-Y < 2 2. Y-X 3 31 May 2009, 21:46
Is x + y < 1? C1. x < 8/9 C2. y < 1/8 2 16 Jun 2006, 17:12
Is x<2? 1) x+y <2 2) x^2+y^2<4 2 04 Mar 2006, 08:54
If xy < 2, is y < 1? (1) x > 2 (2) y < 2 1 07 Aug 2005, 04:54
Display posts from previous: Sort by